I. Field of the Invention
The present invention relates generally to the field pull bar screens and more particularly to a pull bar screen apparatus and system.
II. Description of the Related Art
Fixed frame screens have been used for seasonal placement typically to prevent insects from entering into houses while having windows open. Fixed frame screens are either left in place permanently or are taken out in the off-season for storage in attics, basements and the like. The fixed frame screens typically represent perpetual maintenance problems because they are frail. In contrast, retractable screen systems are housed in a cassette that is permanently mounted to a portion of either a door or window frame and never need to be removed for storage. When not in use, they simply retract into the permanently mounted cassette. Retractable screens have also increased in popularity for use as sun screens.
In manufacturing retractable screens, there are several flaws that reduce the overall quality and structural integrity of the retractable screen product. Typically, high frequency welding is used to connect a screen sheet between two flaps of a vinyl strip, which is pre-positioned within a channel of an extruded pull-bar. The high frequency welding applies electronically controlled quantities of heat and pressure to weld one side of the screen to the vinyl strip. The sheet of screen is welded after the positioning of the vinyl strip. FIG. 1 illustrates a top exploded view the constituent components of a prior art pull bar apparatus 50. As described above, the apparatus 50 generally includes a cassette holder 55 in which the retractable screen material 60 is held. A vinyl strip 70 is welded to a lower end of the screen 60. A high frequency weld 65 is used to connect the screen 65 and the vinyl strip. In general, a pull bar 75 is then connected to the vinyl strip and a portion of the screen 60 to cover the weld 65.
In general, it is appreciated that imperfect positioning of the unsupported sheet of screen often occurs. In addition, there are uneven expansion factors between the screen and the strip thereby causing unsightly wave patterns in the screen. Therefore, the vinyl strip is typically the flaw of present retractable pull screens. However, in order to retain aesthetic appearance, this process continues to be used.